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Solving the cold case: Time, DNA and ingenuity can help

Editor's Note: As part of CNN.com's new Crime section, we are archiving some of the most interesting content from CourtTVNews.com. This story was first published in 2002.

(Court TV) -- In March 1985, 30-year-old James Larkins was found shot to death in his car. Miami-Dade detectives knew only that Larkins was involved in selling cocaine and that no one wanted to talk. The case quickly grew cold.

It took 15 years -- and the testimony of two men who agreed to name the killers in exchange for lighter sentences in unrelated cases -- to solve the murder.

Sometimes the passage of time is all a cold case -- one that has gone unsolved for years -- needs to generate heat.

"Over time people's relationships with each other change," says Detective Gary Smith, supervisor of the Miami-Dade Cold Case Squad. "Friends are no longer friends. People divorce. They might find religion. So those people who didn't give information before might now be willing."

Although it seems like the cops just got a random break in the Larkins case, the case is a typical of how detectives can exploit the passage of time to solve open cases, says Smith, whose unit was one of the first in the nation established to investigate cold cases. To uncover new leads, cold case detectives -- typically some of the most experienced in their field -- will re-interview old witnesses and family members hoping they may provide new information.

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"We find time has been an ally," says Sergeant Bill Tanton, a 23-year veteran of the Sacramento Police Department and a consultant for the California Cold Case Investigation Course, a training program that specializes in solving open cases. "Particularly in gang-related cases a lot of these young kids have changed their minds and grown-up and realized what they were involved in."

It took nearly four decades for witnesses to come forward in the infamous Schuessler-Peterson murders in Chicago. The naked, bruised, strangled bodies of three boys were found piled on top of one another in a forest preserve in 1955.

The case remained one of the city's great unsolved crimes, until in 1993, police found four men who admitted that a man named Kenneth Hansen had confessed to the murders.

The men had not come forward earlier, they said, because three of them had had a sexual relationship with Hansen and at least one said he feared the social stigma if the relationship became public. One of the men said he had been molested by him.

Over the years, all four men ended up in prison and agreed to talk after prosecutors offered them deals to testify against Hansen.

The passing of time has helped cold case investigators in another way. Over the years advances in forensic science such as fingerprint, ballistics, and especially DNA testing have allowed for many cases to be solved just by re-examining the old evidence.

"DNA is so sophisticated now, just in the last few years we've been able to move from saying its one in 10,000 people to this is the only person on the face of the earth that will have this DNA profile." explains Sharon Pagaling Hagan, the only recognized criminal investigative profiler for the state of California. "Obviously it changes everything."

A computerized national database called CODIS that stores over a million DNA profiles of known felons can allow detectives to match their unidentified sample with a known criminal. This technology is particularly useful in cases of sexual assault.

Six-year-old Lisa Marie Bonham went missing while visiting relatives in Reno in 1977. Twenty-three years later detectives asked for her recovered clothing to be retested. Scientists found previously undetectable DNA evidence and matched it with that of Stephen Smith, a convicted felon.

Through CODIS, investigators can positively identify their suspect in as little as a few hours. The CODIS system can also help investigators more easily link a series of crimes to one person as was the case of the recent Long Beach rapist. In November, California police linked Mark Wayne Rathbun to 13 sexual assaults using DNA evidence that is so compelling even the suspect's mother believes he did it.

Although improper storage such as using plastic bags rather than paper or exposing the evidence to too much humidity or heat can degrade DNA, Hagan says that current technology can even recover complete profiles from poorly stored evidence, the kind usually available in very old cases.

"If somebody's hands are sweating and they touch something, we can recover their DNA from that," she says.

Advances in DNA technology have allowed investigators to solve cases by retesting evidence, but some cases get cracked through innovation or by detectives thinking outside the box.

Sergeant Jorge Duran, supervisor of the San Diego cold case unit, has used the media to close old cases. He recalls the case of Gilberto Araiza, who, along with an accomplice, fatally stabbed a city shuttle bus driver in 1983.

When his accomplice ratted him out, Araiza fled to Mexico where he remained in hiding until 2000 when Duran got a Latin American television program similar to "America's Most Wanted," called "Primer Impacto," to run a segment on him. Within days they received a call from Mexico. Araiza is now serving life without parole.

And then there are some cold cases that, once reexamined, turn out not to be murders at all.

In an isolated area of California, Tanton recalls, a woman was found with part of her face lying under some bushes. The murder weapon, a handgun, was eight or nine feet away. The assailant, police surmised, shot her gruesomely in the face, then dropped the gun as he or she fled the scene. But what seemed particularly odd was that the handgun didn't seem powerful enough to have blasted part of her so far away. The answer it turned out was simple: Animals had altered the crime scene. The woman had shot herself.

And, of course, there is the occasional lucky break. Recently, Vallejo, California, authorities were able to recover a 6-year-old boy kidnapped when he was just two weeks old after his mother and grandmother were killed in a fire. Police received an anonymous tip leading them directly to the suspect. The boy will be reunited with his true family soon.

Cold case investigators say they work on the open cases out of a sense of obligation to the victims and their families.

"On some occasions it does happen where the investigator gets to know a lot about the victim by interviewing their friends and family..." says Duran. "And [he] gets a sense of wanting to bring this to a close because this person didn't deserve this."E-mail to a friend